European patent publication number EP 0899701 describes a security light that has tracking means for moving the security light to focus on a moving object detected by a sensor arrangement that initially detects the general direction in the form of a sector shaped field with respect to the location of the security light and thereafter finely tracks the moving object to focus a beam of light reasonably accurately in the direction thereof. The difficulty with this arrangement is that it is costly because of the rather complicated arrangement of sensors and control mechanism, and it is furthermore considered by applicant, to be unnecessarily complex having regard to the generally diffuse nature of light emitted by a typical security light.
Applicant's own proposal that is published as international patent publication number WO2007147179 describes a security device that includes a somewhat simplified security light that includes multiple sensors and a motor for rotating the security light to one of multiple directions according to movement detected by a sensor. This publication is, however, silent as regards any practical, cost-effective security light that can be manufactured relatively inexpensively and that is substantially maintenance free.